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UNITED STATES PATENT OFFICE.

ERNEST G. SCOT, OF PORT SUNLIGHT, NEAR BIRKENHEAD, ENGLAND,

' ASSIGNOR TO LEVER BROS, OF SAME PLACE.

PROCESS OF EXTRACTING OIL.

SPECIFICATION forming part of Letters Patent No. 465,031, dated December 15, 1891;

I Application filed June 29, 1889. Serial No. 316,057- (No specimens.)

To all whom, it may concern.-

Be it known that I, ERNEST GEORGE SCOTT, of Port Sunlight, near Birkenhead, in the county of Chester, England, have invented certain new and usefullmprovements in the Process of Extract-ing Oils, of which the following is a specification.

Seeds and other materials have been deprived of their oil and grease by means of carbon bisulphide applied to dissolve out the oil. This is preferably done in a series of vessels, or what is commonly known in the art as methodical treatment, the fresh carbon bisulphide in such case attacking the nearlyexhausted seed or other material and the nearly-saturated bisulphide being made to act last on nearly fresh seed or other material, the carbon bisulphide being afterward distilled from the grease. There are several disadvantages in this process which have prevented its general adoption. They are principally that the fumes of carbon bisulphide are very disagreeable and deleterious to the health of the workmen; second, that they are very inflammable, and, third, that they leave a very disagreeable odor or taste in the oil or grease obtained, making it useless for manypurposes. Now I have discovered that by thesubstitu tion of carbon tetrachloride for carbon bisulphide very great advantages are attained,both in the course of manufacture and in the character of the product, the disagreeable and poisonous fumes being avoided, the danger of fire by the use of tetrachloride is superior to that obtained by the use of bisulphide.

In making use of carbon tetrachloride I may employ the same apparatus, and the same steps that are now employed for the extraction of oil with carbonbisulphide,exce ptthatI substitute for the latterthe tetrachloride. The old apparatus and process are known in various slightly-modified forms to every practical chemist 'of the present day. One of the procedures in which the carbon tetrachloride may be employed is to provide a series of closed receivers to contain the seeds or other material to be treated. The tetrachloride will be passed through the receivers in succession, commencing with that containing the nearly-exhausted material and ending with that containing fresh material. Thus the more saturated tetraehloride will take up the oil from the freshest material and the fresh tetrachloride Will take up the oil from the nearlyexhausted material. When the material in one receiver is exhausted, it is cut ofi from the rest and a fresh receiver connected to the end of the series. The receiver which is cut off has steam passed through it to blow out the fluid contents, after which the saturated tetrachloride of carbon is distilled. off, leaving the oil behind. The material from which the oil is to be extracted is sustained in areceiver upon a false bottom and the tetrachloride placed in the bottom with a heating appliance usually a steam-coil. The coil vaporizes the tetrachloride, which rises through the material and extracts the oil, which percolates down with the tetrachloride into the space below the false bottom. The base being hotter than any other part, the tetrachloride is again vaporized, leaving the oil behind. This goes on repeatedly and continuously until the greater part of the oil is extracted. The apparatus is then permitted to cool and the tetrachloride and oil delivered into a vessel, where they are separated.

The employment of tetrachloride carbon as a solvent in my process is not only advantageous as compared with bisulphide of carbon,- but also as compared with any other solvent known at the present day-such, for example, as chloride of methyl or chloroform.

Chloride of methyl is a gas under ordinary circumstances and can be used only under pressure, so that its use would demand a totally different apparatus and be commercially impractical in the methodical process. where, too, a gas like chloride of methyl is used under pressure, the risk of loss is infinitely greater than when a comparatively stable liquid is used. Moreover, the risk of accident is tremendous and the breakage of a pipe or other cause of leakage would be attended with fatal results to workmen in the vicinity.

Chloroform is absolutely useless for the practical or commercial extraction of oil. Its boiling-point is 62 centigrade, far below that of tetrachloride of carbon. This is an exceedingly important diflference, as the greater the specific gravity or density of the solvent the more marked is the difference between it and the specific gravity of the solution of oil therein. Consequently with the tetrachloride there is far greater tendency for the solvent as it becomes saturated with the oil to rise to the top. The result is that with chloroform it is practically impossible, even with the methodical process, to get a thoroughly-saturated solution, except by very long contacts and a great number of chambers, while with tetrachloride of carbon, owing to its specific gravity, the solution rises to the top, so that by the use of one or two chambers a saturated solution may be obtained. Thus a great reduction in the size and cost of the plant is permitted with a corresponding cost in the cost of maintenance and in leakage.

Again, chloroform being very volatile as compared with the tetrachloride, there is much less waste in using the latter. Moreover, the use of chloroform is attended with very great danger by reason of the anaesthetic vapors given oft, whereas the vapor of tetrachloride at ordinary temperatures will not act antesthetically except under long and continuous exposure thereto. It will be observed, therefore, that the employment of tetrachloride is highly advantageous not. only as regards economy of manufacture and safety to the at tendants, but also as to the quality of the product.

Having thus described my invention, what I claim is 1. As an improvement in the art of extracting oil or grease from seeds or other substances, digesting the said materials with carbon tetrachloride until the oil or grease is ex- .two subscribing witnesses.

ERNEST c. soor'r.

\Vitnesses:

JOSEPH J. Korean, H. P. SHOOBRIDGE. 

